The Law is DeadKill your first Damned Zombie.

This should unlock through natural progression of the story. Damned zombies are different than regular zombies. Be sure it is actually you that kills it and not your teammates so you get the trophy. The first place to get this is 02: New Sheriff in Town, when the fat zombie that spews poisonous stuff comes out. Use your Pwnage () with every character to defeat him.

Hard WorkerComplete all Objectives listed for any chapter.

Got Pwnage?Use each character's Pwnage ability 10 times.

To use the Pwnage ability, press . You will need to use this 10 times, with each character. Meaning you will have to use it collectively 40 times across the entire game. Grinding may be needed, but just try to use Pwnage whenever you can.

Weapons ExpertPick-up all five mash-up weapons with each character.

You will find these weapons scattered throughout the levels. If you walk over them, you acquire them with whatever character you have at the time. These weapons are:

Chainsaw

Flare Gun

Nail Gun

Flamethrower

Grenade Launcher

You need to pick up each weapon with each character, meaning all five weapons have to have been held by all 4 characters. An easy way to do this is in level 10, since it has each of the different weapons in it. Use the first weapon until it expires, then you can use another player on the weapon and repeat. If you haven't been keeping track of your progress this is a life-saver. This trophy is cumulative throughout all levels.

Money GrubberCollect $20,000 in a single chapter.

Easily obtainable in 02: New Sheriff in Town. Use Jeremy (the gamer) because of his SMG that can kill fast and easy (or anyone else you feel comfortable with). Sit next to the Donut on the crane and kill the zombies coming up to you. Then collect the green orbs (money) until it shows in the top right side of the screen that you have $20,000.

Beacon in the DarkSurvive a fortnight in Blackout Mode.

Blackout mode is unlocked after beating the game once. Blackout mode is where the the lights are turned off for extra difficulty. You can turn up the brightness for a little help. You need to survive 15 nights to unlock this trophy. The higher the number the harder it gets, but just keep close to your teammates and use your zombie bait and Pwnage when you can. This can be done online, offline or singleplayer.

Long Term Survival PlanYou survived 30 Days in Survival: Classic.

This mode is unlocked after beating the game once. Use the tips in Exhausted and strategies you have picked up during your singleplayer game. Survive 30 days and this trophy will ding. This can be done in online, offline, or singleplayer.

Super SaviorBring all possible survivors to Def Money's yacht in Story Mode.

In 10: We're on a Boat, Mother$#@#er, upon finishing the level the credits will roll yet you can still move, with Def Money's yacht accessible. Survivors will be running to the yacht. All you have to do is kill the zombies that are trying to stop the survivors from boarding the yacht. Once all of them reach the yacht, this trophy will pop.

Playing with PowerGet all 100 upgrades for your characters.

To upgrade any item in this game, you must use/do whatever it is that you are upgrading. Then, if you have collected enough money, you can purchase the upgrade and have it. Then you do this again for all 5 levels of the 5 different upgradable things. When you actually have unlocked an upgrade a message will pop up above the character's head saying "X - Lvl X" which means you have that level available for purchase. These upgradable things are:

Speed - You can level this up by running a lot, just run around to dodge zombies to unlock these 5 levels

Primary Weapon - Kill zombies and use the weapon a lot to unlock the levels

Melee Weapon - To use the melee weapon, press and this will level up quickly

Zombie Bait Special - Each character has a different zombie bait, press to use it

Pwnage Ability - Use Pwnage enough to level up and unlock the levels. Try to get Got Pwnage? at the same time

You can purchase these upgrades at the end of a level for each character. Grinding may be needed as well, replay any level you want (2 and 4 are good places).

Note: This must be done in singleplayer, do not attempt in co-op.

Also Note: This trophy has been known to glitch randomly, so if you have all of the upgrades and the trophy doesn't unlock, you will have to redo everything on a fresh save, sorry to say.

Epic RunComplete a Story Mode: New Game with 3 other players.

This has been reported that it needs to be completed in online co-op. It has also been reported that you have to do it in one sitting, no one can leave during your zombie massacre. Find 3 friends or boosting partners to spend a few hours with and just beat the game for this trophy. Use the boosting thread to find some partners.

ExhaustedComplete All Chapter Objectives.

There are multiple chapter objectives for each level. They consist of: Kill x amount of zombies, or Get x amount of points. Replays are possible and advised. There is a glitch reported, if you play online co-op and try to do this. It won't unlock, but if you keep track of the objectives you did online, repeat them again in singleplayer to get the trophy. Here is a run down and general tips:

Complete levels quickly, there are objectives for completing them under a certain time limit. Speed through the level while taking out zombies.

In groups of zombies, stick with one character to get the multiplier up, and score a lot of points while killing the zombies.

Save the survivors. You see survivors in the levels, and are asked to save them. This means protect them until you get to the drop-off point. When you drop them off, that will count as saving them.

Take as little to no damage in the levels. Use your AI teammates as blockades if you need to (just hide behind them). But don't run into groups of zombies. When you see a group, stay and hold the fort together with your team.

Use each character's Pwnage ability for the boss fights to make it a lot easier.

For the specific machine kills, eg. Kill 20 Enemies with the Flying Donut, the characters will talk about the thing so you know what it is you actually need to kill zombies with (if it wasn't obvious already).